Substance composition and method for melting ice and preventing slipperiness and use of betaine for melting ice and preventing slipperiness

ABSTRACT

The invention relates to a combination of compounds for de-icing and/or anti-skid treatment, which combination comprises betaine and at least one other de-icing agent, which has been selected from the group consisting of acetates, formates, urea and combinations thereof. The invention also relates to a method of de-icing and/or anti- skid treatment, wherein a combination of compounds selected from the group consisting of acetates, formats, urea and combinations thereof, are applied to a slippery surface or a surface vulnerable to slipperiness. The invention further relates to the use of betaine for de-icing and/or anti-skid treatment, when betaine is used in combination with at least one other de-icing agent, which has been selected from the group consisting of acetates, formates, urea and combinations thereof.

FIELD OF THE INVENTION

The present invention relates to a substance composition comprisingbetaine for melting ice and/or preventing slipperiness, or, in otherwords, for de-icing and anti-skid treatment. The invention also relatesto a method for melting ice and/or preventing slipperiness by using thesubstance composition in question, as well as the use of betaine for thesame purpose.

BACKGROUND OF THE INVENTION

The prevention of ice-formation and slipperiness is extremely importantat airports in order to maintain safe conditions for take-off andlanding as well as for general aviation safety. The most importantrequirement for the anti-skid treatment at airports is ensuring aviationsafety by maintaining sufficient friction on the asphalt surface of therunway. There is a certain friction requirement for runway paving, andthis must be fulfilled whenever there is air traffic at the airport. Thecoefficient of friction is a constant that describes the interfacebetween two solid substances, and it expresses the amount of frictionpresent as the bodies slide against each other. The coefficient offriction is always more than zero and in practice always less than one.As far as the friction requirement at airports is concerned, the valuemust usually be at least 0.3, preferably 0.4.

Mechanical methods are primarily used for anti-skid treatment onrunways. Chemical melting agents are required for removing the hoarfrostand ice formed on the runway surface, as well as for anticipatoryanti-skid treatment. In general, ice-melting agents are used for theanti-skid treatment, optionally with added thickeners in order toincrease viscosity, as well as water, surfactants and corrosioninhibitors. The purpose of the ice-melting and anti-skid agents is todisrupt and weaken the adhesion of the ice to the surface of pavement,after which the surface can more easily be mechanically cleaned. For theprevention of slipperiness on roads, chlorides have mainly been used asice-melting and anti-skid agents. The substances that are used in roadmaintenance, such as sodium chloride, could not be used at airports,since they rapidly rust and erode the metal parts of the planes as wellas airport equipment. In addition, chlorides have a harmful effect ongroundwater quality, soil, vegetation and soil microfauna.Traditionally, water-soluble organic compounds such as urea have beenused for melting ice at airports. However, the use of urea has largelybeen given up, since it has been found to cause significantenvironmental damage, especially due to nitrogen's eutrophicatingeffect. As a result of the use of urea, oxygen depletion may occur ingroundwaters, increasing the dissolution rate of heavy metals. Atpresent, acetates, liquid potassium acetate and solid sodium acetate, aswell as formates, potassium formate and sodium formate, are used atairports. In comparison to chlorides and urea, acetates and formates areless detrimental to the environment. Acetates and formates are effectivein melting ice, but their drawback comprises the heavy corrosion ofmetals and electrical equipment. After the introduction of ice-meltingagents based on acetate and formate, issues with asphalt pavements havebeen observed at airports. What is also significant in relation to thepresent invention is the fact that ice-melting agents based on acetateand formate have been found to cause heavy corrosion in aeroplanematerials, including carbon fibre brakes, metal surfaces and matingmetal-metal surfaces. All these issues caused by nominal deicing agentsincrease the risk of aviation safety.

In anticipatory slipperiness prevention, liquid ice-melting agent hasbeen found to be the most usable form of an ice-melting agent, since asolid and often granular ice-melting agent is easily carried away fromthe intended surface under the influence of air flows. Further, theeffect of granular ice-melting agent is very local, and therefore theeffect starts fairly slowly and the applied amount is substantiallyhigher than when a liquid or wetted substance is used. Liquidice-melting agent is more easily distributed over the entire surface,thus covering a substantially larger proportion of the pavement surfacethan a solid substance. Previously, liquid substances comprising about50% water have usually been used for the removal of hoarfrost and thinice. To remove thicker ice, granular substances are required, which meltthe ice down to the surface of the runway if necessary, after which thesurface is cleaned by snowploughing or brushing. At present, liquidsubstances are mainly used (nearly 80% of all substances used) for theanti-skid treatment at airports, since a thick layer of ice is rarelyallowed to form on the runway.

As a result of better understanding, environmental considerations andespecially the accumulation of chemicals and their effect on theenvironment have gained increased significance. Especially in view ofthe environmental considerations concerning the former ice-meltingagents, there is a great need for developing novel ice-melting agentsthat possess the efficacy necessary in the prevention of slipperiness.

EP 1034231 discloses a composition for anti-skid treatment in whichaqueous solution comprising 10-60% betaine or its derivatives is used asan anti-freezing agent for runways and as an anti-skid agent forrunways.

U.S. Pat. No. 6,596,189 discloses a liquid-based anti-freezingcomposition for airport runways, the composition exhibiting a minimalcatalytic oxidative effect on carbon-carbon fibre composite brakes. Thiscomposition comprises mixtures of alkali and alkali earth metalcarboxylates and alcohols, into which additional corrosion inhibitorshave been added.

BRIEF DESCRIPTION OF THE INVENTION

The invention relates to a substance composition for melting ice and/orpreventing slipperiness, the composition comprising a combination ofbetaine and another ice-melting agent selected from the group consistingof acetates, formates, urea and mixtures thereof. The combination of theinvention is an effective de-icing and/or anti-skid combination ofbetaine and said other ice-melting agent.

In one embodiment of the invention, betaine is present as a solution andat least one other ice-melting agent is present in a solid form. Thecombined use of a solid and a liquid ice-melting agent is based on thatthe solid ice-melting agent bores through the ice, reaching the pavementsurface, and this makes it possible for the liquid ice-melting agent torun through the formed hole and enter between the ice and the pavementsurface, separating the ice from the pavement surface. The compositionmost preferably comprises a combination of a betaine solution with solidsodium formate and/or sodium acetate.

The invention also relates to a method for melting ice and/or preventingslipperiness, wherein a composition comprising a combination of betaineand another ice-melting agent selected from the group consisting ofacetates, formates, urea and mixtures thereof is added to a surface thatis slippery or that is liable to become so. The combination is effectivein providing de-icing and/or anti-skid treatment of the surface.

Further, the invention relates to the use of betaine for melting iceand/or preventing slipperiness, wherein betaine is used in combinationwith at least one other ice-melting agent selected from the groupconsisting of acetates, formates, urea and mixtures thereof. Thecombination of betaine and said other agent provides a de-icing and/oranti-skid effect.

The composition according to the invention is applied to the desiredapplication target, including airports, roads, bridges, stairs, yards,pavements and ramps, as well as certain special road sections thatrequire anti-skid treatment. Betaine is used in an amount that issufficient to provide, together with the other ice-melting agent, anefficient effect in regard to melting ice and preventing slipperiness.In a preferred embodiment of the invention, betaine provides asynergistic effect with the said other ice-melting agent. Betaine isalso used for diminishing the corrosive effect in melting ice, fordiminishing the negative effects of ice-melting agents on the abrasionresistance of the treated target, for diminishing the detrimentaleffects of ice-melting agents on the environment, for decreasing theeffect of ice-melting agents on the wear of the components of thecarbon-carbon fibre composite breaks used in aeroplanes, for decreasingthe pollution of the groundwaters caused by ice-melting agents and fordiminishing the migration of PAH compounds into the environment causedby ice-melting agents.

DETAILED DESCRIPTION OF THE INVENTION

It has been found that the improved effect obtained by the combinationof betaine with acetate, formate or urea provides already with a minoramount of the other melting agent an effective ice-melting agent oranti-skid agent, also providing an alternative that is both lesscorrosive and more environmentally friendly than the previously usedice-melting agents mentioned above. Also the lower toxicity of thecombination makes it an excellent alternative for use in anti-skidtreatment.

As used herein, the term “composition” refers to one or more substances,which may be in a mixture or separately, independently from each other,in a solid form or as solutions. A typical composition consistsessentially of a combination of two active ice-melting and/or anti-skidagents. The term composition includes the application of the saidsubstances on the treated surface simultaneously or separately, howeverin such a way that the substances are adapted to provide a singlede-icing and/or anti-skid action. The best action is provided throughthe synergistic effect of the said substances. According to theinvention, the substances that form the composition, betaine and thesaid other ice-melting agent in solution and/or as solids, may be mixedeither before the application or in connection with the application.

As used herein, the term “betaine” refers to trimethyl glycine,trimethyl glycine monohydrate or the active derivatives thereof. Theactive derivatives refer to organic salts of trimethyl glycine, such ascitrates, acetates and formates, which form betaine in aqueoussolutions. Betaine is usually derived from natural sources, for instanceextracted from sugar beet or obtained by biochemical processes. Reportsshow that betaine causes no more corrosion than regular water. Theadhesiveness of betaine onto metal surfaces is weak, and it does notcause oxidation of carbon fibre brakes.

As used herein, the term “ice-melting agent” refers to a de-icingsubstance the purpose of which is to prevent the formation of ice, i.e.to function as an aid in anticipatory anti-skid treatment and/or to meltdown and separate already formed ice or hoarfrost, which may then beremoved from the surface by mechanical methods, for instance by brushingor snowploughing. The other ice-melting agent referred to in thisinvention signifies urea, acetates, formates and/or mixtures thereof.

As used herein, the terms “slipperiness prevention” or “anti-skidtreatment” refer to those measures the purpose of which is theprevention of surface slipperiness and formation of ice. Slipperinessprevention or anti-skid treatment may also refer to the melting ofalready formed ice and its removal by chemical or mechanical means.according to the invention have been approved by the SAE AerospaceMaterial Specification (AMS 1435) standard concerning the relevantchemical.

The combination according to the invention is substantially free ofcorrosion inhibitors, or the amount of corrosion inhibitors in thecombination is substantially smaller than in a corresponding combinationthat provides a similar ice-melting effect but does not comprisebetaine. True to their name, corrosion inhibitors are typically added toanti-freezing agent compositions to slow down or to prevent thecorrosion caused by the substances to the surface. In corrosion, thematerial is damaged due to the effect of the environment, either bydissolving or by otherwise reacting with the surrounding substances.

The temperature of the anti-freezing agent composition may at thebeginning of the application be that of the surrounding air, forinstance between −20° C. and +10° C., but the inventors have discoveredthat warming significantly improves the melting efficiency. According tothe method referred to in the invention, the temperature of betaine hastherefore been raised above atmospheric temperature, for instancebetween +10° C. and +100° C., a preferable application temperature beingbetween +20° C. and +60° C. When the said other ice-melting agent isapplied as a mixture with betaine, the application temperature of thecombination is in accordance with the above-presented range.

According to the invention, the amount of the melting agent combinationapplied on the runway is 5-200 g/m², preferably 10-50 g/m². Since theamount of substance required for the anti-skid treatment at airports isusually at least 1-2 tonnes, it is important that the used ice-meltingagent is environmentally friendly and safe for the airport crew tohandle. The adverse effects caused by the combination according to theinvention have been found to be clearly smaller than the adverse effectscaused by other, previously-used substances that provide a similarice-melting effect.

The equipment used for the application of ice-melting chemicals atairports comprises largely the same equipment as is used for roadmaintenance, i.e. disc and spray applicators. The only differenceconstitutes the size of the application devices, at airports the size ofthe applicators is 3-fold as compared to road maintenance equipment. Bydisc applicators, solids and solutions may be applied simultaneously,whereas a spray applicator can only be used for applying a solution.

The application targets of the invention include airports, roads,bridges, stairs, yards, pedestrian crossings, pavements and ramps aswell as certain special road sections that require special attention inthe prevention of slipperiness. The most important places as far as theprevention of slipperiness is concerned are those where slipperiness islikely to cause danger. The anti-skid treatment is started immediatelywhenever a change in the weather conditions might lead to a significantincrease in slipperiness.

According to the invention, betaine and the said other ice-meltingagent(s) are, independently from each other, applied in a solid form orin the form of a solution. In a preferred embodiment, betaine is appliedas a solution and the said other ice-melting agent is applied in a solidform. Preferably, the said solid substance is sodium formate.

The amount of the at least one other ice-melting agent in thecombination is sufficient to improve the ice-melting and/or anti-skideffect obtained with betaine. Furthermore, the amount of the said otherice-melting agent is preferably sufficient to produce, in combinationwith betaine, a synergistic effect in regard to melting ice andpreventing slipperiness. In the experiments, it was surprisingly foundthat even a very small amount of the other ice-melting agent issufficient to significantly improve the ice-melting capability of thebetaine solution and that the combination still provides significantimprovements in regard to corrosion and environmental effects.

In combination with the other ice-melting agent, betaine providesseveral advantages in comparison with other combinations that produce asimilar ice-melting effect but do not comprise betaine. The compositionhas a lower corrosive effect, it has a less negative impact on theabrasion resistance of the application target, especially diminishingdamages to coatings, has a smaller detrimental effect to the environmentand its effect on the wear of the components of the carbon-carbon fibrecomposite brakes used in aeroplanes is smaller as compared to othercombinations that produce a similar ice-melting effect but do notcomprise betaine.

The effect of the betaine combination on diminishing the pollution ofgroundwaters caused by ice-melting agents is significant. Ice-meltingagents are usually water-soluble, and as they are released into nature,they leach into groundwaters, whereby the earlier-used harmfulsubstances cause environmental issues. The pollution of groundwaters bychlorides is a significant problem on busy roads. Therefore, preventingthe pollution of groundwaters constitutes an extremely importantenvironmental issue.

The ice-melting agents in use today can cause the migration of PAHcompounds into the environment by extracting them from the bitumen thatis used as a binder in asphalt. The PAH compounds are polycyclicaromatic hydrocarbons, which accumulate in the food chain. Their mostimportant health hazard comprises their ability to cause cancer. Thebetaine combination has made it possible to diminish the migration ofPAH compounds into the environment caused by the ice-melting agents.

The following examples illustrate the invention and are not intended tolimit its scope in any way. The percentages in the examples arecalculated by weight, unless otherwise specified.

EXAMPLE 1

In the test, the melting efficiency of different combinations ofice-melting agents and different mixture ratios were compared to eachother in relation to time. The tested combinations consisted essentiallyof the two ice-melting agents and water. In the test, the penetrationefficiency into ice in relation to time was measured by first addingsolid substance onto the surface. After 30 minutes, the depth of thehole that had melted into the ice was measured, after which the liquidice-melting agent was furthermore added. The depth of the hole wasmeasured at 10, 30 and 60 minutes after the addition of the aqueoussolution. During the entire test, the test temperature was −2° C. Theexperiment was ended after 90 minutes, since it is known thatice-melting agent dilutes into the molten ice, its efficiency thus beingdiminished logarithmically as a function of time.

The experimental solid-liquid substance mixture ratios and thecorresponding amounts of substance are presented in Table 1.

TABLE 1 Mixture ratios and amounts of substance in different series.Solid Liquid Series 1 Mixture ratio 14.2%  85.8% Amount of 21.45 130.05substance (mg, μl) Series 2 Mixture ratio 33.3%  66.7% Amount of 49.95 99.9 substance (mg, μl) Series 3 Mixture ratio 60%  40% Amount of 90 60 substance (mg, μl)

Tables 2-4 present the obtained results and errors (mm).

The melting efficiency of solid sodium formate and aqueous betaine islower than that of sodium formate alone, but the combination comprisingsodium formate and betaine proved fairly efficient at all mixtureratios. The results show that even a minor amount of sodium formatesignificantly affects the melting efficiency of betaine. The meltingefficiency obtained by using a combination of sodium formate withbetaine is about 100% higher than the melting efficiency of pure betainemixture at all mixture ratios.

TABLE 2 Results and errors (mm) for substance mixture comprising 14.2%solid substance and 85.8% liquid solution (50% concentration). Time(min) 30 40 60 90 Solid Liquid Result Error Result Error Result ErrorResult Error Betaine Betaine 2.9 0.0 4.5 0.0 5.8 0.0 7.3 0.1 Na-formateBetaine 6.4 0.1 9.1 1.3 11.1 0.8 13.4 0.5 Na-formate K-formate 6.4 0.211.4 0.7 14.3 0.8 17.9 0.6 Betaine Xylitol 3.2 0.1 4.6 0.6 5.8 1.6 6.92.0 Xylitol Betaine 2.4 0.2 4.8 0.1 5.7 0.2 7.1 0.2

TABLE 3 Results and errors (mm) for substance mixture comprising 33.3%solid substance and 66.7% aqueous solution (50% concentration). Time(min) 30 40 60 90 Solid Liquid Result Error Result Error Result ErrorResult Error Betaine Betaine 4.4 0.1 5.9 0.1 7.3 0.0 8.8 0.1 Na-formateBetaine 7.4 0.8 9.3 0.7 11.7 0.1 13.0 0.2 Na-formate K-formate 8.7 1.213.8 0.7 16.5 0.3 19.6 0.2 Betaine Xylitol 4.1 0.1 5.3 0.1 6.2 0.0 7.30.0 Xylitol Betaine 3.7 0.1 5.1 0.1 6.8 0.0 8.1 0.5

TABLE 4 Results and errors (mm) for substance mixture comprising 60%solid substance and 40% aqueous solution (50% concentration). Time (min)30 40 60 90 Solid Liquid Result Error Result Error Result Error ResultError Betaine Betaine 4.8 0.3 6.2 0.1 8.0 0.1 9.6 0.1 Na-formate Betaine9.7 1.9 13.7 2.2 16.8 4.0 20.4 4.4 Na-formate K-formate 10.8 2.3 17.02.0 19.7 2.7 23.1 2.5 Betaine Xylitol 5.3 0.1 6.2 0.2 7.2 0.2 8.6 0.2Xylitol Betaine 4.5 0.1 5.6 0.1 7.5 0.3 9.5 0.8

EXAMPLE 2

Normally, the temperature of the ice-melting agents equals the outdoortemperature. This experiment investigated the effect of a warmedice-melting agent on melting efficiency. The melting efficiencies ofsubstances were studied at the temperatures of 20° C. and 60° C. Duringthe entire test, the test temperature was −2° C. Table 5 presents theresults and errors (mm) for warmed substances. Warming affects themelting efficiency of the substances to some extent. The dosages of thesubstances presented in the table have been calculated such that a sameamount of solid melts the ice.

When the application temperature of betaine (50 and 65%) was 60° C., themelting efficiency of the substance was approximately 20-34% higher thanthe efficiency at an application temperature of 20° C. At an applicationtemperature of 20° C. the melting efficiency of betaine in 60 minuteswas 47% of the melting efficiency of potassium formate. At the initialtemperature of 60° C. the corresponding proportion was 53%. Warmingpotassium formate does not result in a similar additional benefit inmelting efficiency as by betaine.

Initial warming of the substances affects the melting efficiency ofbetaine relatively more than that of potassium formate. If initialwarming of the substance in used as an aid in slipperiness prevention,additional benefits can be obtained in relation to the meltingefficiency of the substance.

TABLE 5 Results and errors (mm) for warmed substances. The betainesolution with 65% concentration was not studied at a substancetemperature of 20° C. Substance temperature 20° C. Substance temperature60° C. Time (min) 10 30 60 10 30 60 Dosage (μl) Result Error ResultError Result Error Result Error Result Error Result Error Betaine 50%184 3.2 0.1 4.8 0.1 6.4 0.1 3.7 0.1 6.2 0.2 7.7 0.2 Betaine 60% 151 2.80.1 5.2 0.1 6.1 0.1 3.8 0.0 5.9 0.1 8.2 0.1 Betaine 65% 139 — — — — — —3.3 0.0 6.2 0.1 9.0 0.1 K-formate 50% 150 5.6 0.2 10.1 0.5 13.5 0.8 5.80.1 10.2 0.4 14.5 0.1

EXAMPLE 3

Normally, the temperature of the ice-melting agents equals the outdoortemperature. This experiment investigates the effect of a warmedice-melting agent combinations on melting efficiency. The meltingefficiencies of substance combinations is studied at the temperatures of20° C. and 60° C. During the entire test, the test temperature is −2° C.Table 6 present the results (mm). Warming affects the melting efficiencyof the substances to some extent. The concentrations of pure betaine andpotassium formate solutions are 50 weight %.

When the application temperature of betaine and potassium formatemixture is 60° C., the melting efficiency of the substance is clearlyhigher than the efficiency at an application temperature of 20° C. Ifinitial warming of the substance in used as an aid in slipperinessprevention, additional benefits can be obtained in relation to themelting efficiency of the substance.

TABLE 6 Results (mm) for warmed substances. The combination of 65%betaine solution with 35% K-formate is not studied at a substancetemperature of 20° C. Substance temperature Substance temperature 20° C.60° C. Time (min) 10 30 60 10 30 60 Betaine 50% + 4.4 7.5 10.0 4.8 8.211.1 K-formate 50% Betaine 60% + 3.9 7.2 9.1 4.6 7.6 10.7 K-formate 40%Betaine 65% + — — — 4.2 7.6 10.9 K-formate 35%

EXAMPLE 4

In the test, the melting efficiency of different combinations ofice-melting agents and different mixture ratios were compared to eachother in relation to time. In the test, the penetration efficiency intoice in relation to time was measured by adding liquid substance mixturesonto the surface. The depth of the hole was measured at 10, 30 and 60minutes after the addition of the liquid solution. During the test, thetemperature was either −2° C. or −10° C.

The concentrations of potassium formate and betaine solutions were 50weight-%. The mixture of sodium chloride and betaine contained 23weight-% NaCl and 50 weight-% betaine, because the freezing point of aNaCl solution is at the lowest at a concentration of 23 weight-% and itis used widely in de-icing work. Tables 7 and 8 show the dry content ofthe compounds and also the real calculated concentrations (% by weight).

Mixtures of betaine and potassium formate were effective in melting theice. However betaine does not have a considerable effect on the meltingefficiency of sodium chloride.

TABLE 7 The melting efficiency (mm) of different combinations ofice-melting agents in −2° C. Solution Concentration mixture (mass-%) 10min 30 min 60 min Betaine 10%/K- 50 6.6 11.5 15.9 Formate 90% Betaine25%/K- 50 5.3 8.9 12.3 Formate 75% Betaine 33%/K- 50 4.7 7.9 12.0Formate 66% Betaine 10%/ 25.7 2.8 5.7 8.3 NaCl 23% 90% Betaine 25%/29.75 3.3 6.3 8.7 NaCl 23% 75% Betaine 33%/ 31.68 3.6 5.7 7.8 NaCl 23%66%

TABLE 8 The melting efficiency (mm) of different combinations ofice-melting agents in −10° C. Solution Concentration mixture (mass-%) 10min 30 min 60 min Betaine 10%/K- 50 3.3 4.8 5.6 Formate 90% Betaine25%/K- 50 2.8 4.2 4.6 Formate 75% Betaine 33%/K- 50 2.6 4.3 4.8 Formate66% Betaine 10%/NaCl 25.7 1.7 2.2 2.5 23% 90% Betaine 25%/NaCl 29.75 1.32.1 2.4 23% 75% Betaine 33%/NaCl 31.68 1.2 2.1 2.3 23 mass-% 66%

EXAMPLE 5

In this test, the melting efficiency of different combinations ofice-melting agents and different mixture ratios were compared to eachother in relation to time in a similar 5 manner as in Example 3. In thetest, the penetration efficiency into ice in relation to time wasmeasured in millimeters (mm) by adding liquid substance mixtures ontothe surface. The depth of the hole was measured at 10, 30 and 60 minutesafter the addition of the liquid solution. During the test, the testtemperature was −2° C. all the time.

TABLE 9 The melting efficiency (mm) of different combinations ofice-melting agents in −2° C. Solution Concentration mixture (mass-%) 10min 30 min 60 min Betaine 77%/Na- 50 3.9 6.5 9.1 Formate 23% Betaine85%/Na- 50 3.6 5.9 8.4 Formate 15% Betaine 95%/Na- 50 3.4 5.5 7.6Formate 5% Betaine 77%/Na- 50 3.0 5.3 7.2 Acetate 23% Betaine 85%/Na- 503.1 5.2 6.8 Acetate 15% Betaine 100% 50 2.7 5.1 6.5

1. A substance composition for melting ice and/or preventingslipperiness, characterized in that the said composition comprises acombination of betaine and another ice-melting agent selected from thegroup consisting of acetates, formates, urea and mixtures thereof.
 2. Acomposition according to claim 1, wherein betaine is in the form of asolution and the said at least one other ice-melting agent is in theform of a solid.
 3. A composition according to claim 2, wherein thecombination comprises betaine solution and solid sodium formate.
 4. Acomposition according to claim 2, wherein the combination comprisesbetaine solution and solid sodium acetate.
 5. A composition according toclaim 1, wherein betaine and the said other ice-melting agent are,independently from each other, in a solid form or in the form of asolution.
 6. A composition according to claim 1, wherein betaine and thesaid other ice-melting agent are present in the combination either as amixture or separately, adapted to provide a combined effect.
 7. Acomposition according to claim 1, wherein the combination also compriseschloride and/or other substances.
 8. A composition according to claim 1,wherein the combination is substantially free of corrosion inhibitors orthat the amount of corrosion inhibitors in the combination issubstantially smaller than in a corresponding combination that providesa similar ice-melting effect but does not comprise betaine.
 9. Acomposition according to claim 1, wherein the amount of betaine in thecombination is 30-95%, as calculated on the basis of the total amount ofsolids.
 10. A composition according to claim 1, wherein the amount ofthe said other ice-melting agent in the combination is 5-70%, ascalculated on the basis of the total amount of solids.
 11. A compositionaccording to claim 3, wherein the amount of betaine in the combinationis 30-60%, as calculated on the basis of total amount of solids, andthat the amount sodium formate in the combination is 40-70%, ascalculated on the basis of total amount of solids.
 12. A compositionaccording to claim 1, wherein the amount of the at least one otherice-melting agent in the combination is sufficient to improve theice-melting and/or slipperiness-preventing effect obtained by betaine.13. A composition according to claim 12, wherein the amount of the saidanother ice-melting agent is sufficient to produce, together withbetaine, a synergistic effect in regard to melting ice and preventingslipperiness.
 14. A composition according to claim 1, wherein thecorrosive effect of the combination is smaller as compared to acombination that produces a similar ice-melting effect but does notcomprise betaine.
 15. A composition according to claim 1, wherein thenegative effect of the combination on the abrasion resistance of theapplication target is smaller as compared to a combination that producesa similar ice-melting effect but does not comprise betaine.
 16. Acomposition according to claim 1, wherein the detrimental effect of thecombination on the environment is smaller as compared to a combinationthat produces a similar ice-melting effect but does not comprisebetaine.
 17. A composition according to claim 1, wherein the effect ofthe combination on the wear of the carbon-carbon fibre composite brakecomponents is smaller as compared to a combination that produces asimilar ice-melting effect but does not comprise betaine.
 18. A methodfor melting ice and/or preventing slipperiness, characterized in that asubstance composition comprising a combination of betaine and anotherice-melting agent selected from the group consisting of acetates,formates, urea and mixtures thereof is added to a slippery surface or asurface that is liable to become slippery.
 19. A method according toclaim 18, wherein the substance composition is applied to theapplication target, including airports, roads, bridges, stairs, yards,pedestrian crossings, pavements and ramps, as well as certain specialroad sections that require prevention of slipperiness.
 20. A methodaccording to claim 18, wherein betaine is applied as a solution and thesaid at least one other ice-melting agent is applied in the form of asolid.
 21. A method according to claim 18, wherein betaine and the saidother ice-melting agent are, independently from each other, applied in asolid form or in the form of a solution.
 22. A method according to claim18, wherein the amount of betaine in the composition is 30-95%, ascalculated on the basis of the total amount of solids, and the amount ofthe other ice-melting agent in the composition is 5-70%, as calculatedon the basis of the total amount of solids.
 23. A method according toclaim 18, wherein the amount of betaine in the composition is 30-60%, ascalculated on the basis of the total amount of solids, and the amount ofsodium formate in the composition is 40-70%, as calculated on the basisof the total amount of solids.
 24. A method according to claim 18,wherein the application temperature of betaine is between −20° C. and100° C.
 25. A method according to claim 18, wherein the amount of thesaid at least one other ice-melting agent is sufficient to improve theice-melting and/or slipperiness-preventing effect obtained with betaine.26. A method according to claim 18, wherein betaine and the said atleast one other ice-melting agent are mixed in connection with theapplication or before the application.
 27. A method according to claim18, wherein betaine and the said at least one other ice-melting agentare applied to the surface simultaneously or separately, adapted toproduce a synergistic effect.
 28. A method according to claim 18,wherein the said substance composition is applied to a slippery surfacein an amount that is 5-200 g/m², preferably 10-50 g/m².
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